Fast Passes are able to be made up to 60 days (30 days for offsite guests) before your holiday begins. You get to make up to three Fast Passes per day in advance, but once your three are used up it is possible to add extras.
It can be helpful to plan your Fast Passes around any dining reservations you've made, so you're not bouncing from park to park.
Rides such as Flights of Passage, Frozen Ever After and Na'vi River Journey have super long lines (we're talking hours in some cases) which wastes precious park time. Make sure you get a Fast Pass for the rides on your MUST do list. If you don't quite get the Fast Pass you want keep checking availability. People's vacations change and a golden ticket Fast Pass might suddenly become available.